1. Field of the Invention
The present invention relates to an indoor wireless positioning system and an indoor wireless positioning method capable of calculating a position of a user terminal which moves inside a building.
2. Description of Related Art
Recently, researches on wireless local area network (LAN)-based indoor positioning has been conducted in many countries such as the United States and Europe. For example, the Place Lap project which is being conducted by Intel Corporation may basically measure a position based on a wireless LAN signal value. In addition, a method of estimating a more accurate position by constructing the newest network infrastructure such as Global System for Mobile Communications (GSM), or Bluetooth, radio frequency identification (RFID) is being further studied.
For example, an indoor positioning method using a MOTE sensor network which is a modification of the wireless LAN network when a home service, indoor guidance, etc, are provided is being studied in the ASK-IT project for mobility impaired Europeans.
In addition, there are a radio signal propagation model, a RAdio Detection And Ranging (RADAR) system using a nearest neighbor technique of selecting a position closest to a calculated point, etc. In addition, there are Ekahau's real-time location system, an AeroScout visibility system, etc. as systems which are being commercialized and sold.
In these researches, a plurality of specific positioning methods have been proposed and the proposed positioning methods may broadly be summarized as two methods. One method is a triangulation method used in a global positioning system (GPS) and the other method is a fingerprinting method of dividing a region in the form of a grid as in a cellular network and measuring a position in units of cells.
Although the strength of a signal received from a sensor (or node) is generally utilized to estimate a position of the sensor (or node) in a radio sensor network, there is a disadvantage in that received signal strength (RSS) is sensitively varied by indoor obstacles such as a wall, a floor, and a person.